Structural Safety and Serviceability of Concrete Bridges Subject to Corrosion

Abstract

A structural reliability analysis model is developed to include interaction between transverse cracking, diffusion of chlorides, and corrosion initiation; influence of design specifications on corrosion initiation and propagation; and serviceability limit states (e.g., spalling). The reliability model is used to evaluate probabilities of structural and serviceability failures for flexure and spalling limit states, for a typical reinforced concrete bridge continuous slab. Chloride contamination will occur from the application of deicing salts. It was confirmed that the application of deicing salts caused a significant reduction in structural and serviceability reliabilities; this observation is in agreement with field data of bridge performance. Moreover, the reliability analysis allowed the effect of corrosion to be measured in a quantitative manner. The influence of concrete cover and specified concrete compressive strength was found to be particularly significant on the probability of spalling. The reliability analysis is used to demonstrate how known exceedence of a serviceability limit state (spalling) can be used to update the probability of structural failure. The time-dependent reliability analysis developed in the present paper may, at a later stage, be applied to other reinforced concrete bridge structural configurations or be used as the reliability module in existing inspection, maintenance, or load rating procedures, i.e., bridge management systems.